Decks generally made of wood decking boards are usually constructed with intentional gaps to allow for water to quickly and easily drain therethrough. These decking boards generally need to be stained or painted fairly frequently. Most prior art stain/paint applicators for these applications have not provided a single apparatus that is useful for allowing a user to paint/stain the flat surfaces of the decking boards while simultaneously allowing for the convenient and easy staining of the sides of the boards through the relatively narrow gaps. Instead, users generally have had to employ the use of separate pad-type applicators along with a conventional brush to apply stain both to the planar surface of the decking boards and to the opposed surfaces thereof formed by the gaps. Accordingly, it would be desirable to have a single deck staining/painting tool which could effectively be used to stain/paint both the flat surface of the decking boards as well as the sides thereof.